Sistemas agroflorestais mimetizam ecossistemas naturais e podem ser resilientes frente às mudanças climáticas na Amazônia

Abstract

Although Agroforestry Systems (SAFs) promote various environmental services, especially carbon sequestration and fixation, their role in adapting to climate change and the different ways in which these systems can contribute to the biophysical and geographical contexts of the Amazon region are still scarce. This demonstrates the need for more complete and in-depth research to strengthen understanding of the potential, as well as the exposure and risks to nonanalogous climates that they may be subject to in the near future. This research aimed to analyze the SAFs located in the municipality of Tomé-Açu, in the northeast of the state of Pará, with the following objectives: I) To assess whether SAFs can mimic natural ecosystems in their structure, as well as to assess the stability and ecosystem functionality of these systems over a 20-year time series in the municipality of Tomé-Açu and II) To assess the exposure of SAFs in the municipality of Tomé-Açu to future climate change, considering the increase in Average Annual Temperature (BIO1) and the variation in water availability (BIO12 and BIO15), in an EOCS approach. The results of this research achieved positive responses to the proposed objectives, so that the SAFs in the Tomé-Açu region showed a pattern of EVI behavior over 20 years, without differing significantly from the forests. As for above-ground biomass, although it decreased over time for both covers, it showed some stability, especially in the years 2019 and 2020 for the SAFs. This shows that the SAFs are structurally similar to mature forests. As for exposure to climate change, there were considerable increases in temperatures, from 1.56 °C to 5.4 °C above the current average from the intermediate to the most pessimistic scenario. At the same time, there will be a reduction in accumulated rainfall of between 96 mm and 220 mm by the end of the century and seasonality will increase by around 4-8%, especially in the period 2081-2100. The EOCS for the SAFs is limited to the minimum and maximum of the BIO12 and BIO15 variables, from 2100 to 2300mm and between 70 and 77%, respectively. These ranges guarantee the proper functioning of these systems in the current period, but are under threat in the near future, especially in the SSP5-8.5 scenario. We conclude that in terms of climate exposure, the northwest and central regions of Tomé-Açu will suffer from extreme changes in rainfall reduction and increased seasonality, while the eastern region will be exposed to milder conditions, with some extremes in BIO15, which in a pessimistic scenario, reduce from extreme to medium and low, which may indicate that SAFs are adaptable to future changes. These results are relevant and call attention to the adoption of measures to avoid more critical climate change scenarios for the Amazon region.